Vapor chamber

ABSTRACT

The vapor chamber includes a casing, a working fluid, a microchannel, and a wick. The casing includes an upper casing sheet and a lower casing sheet that face each other and are joined together at an outer edge so as to define an internal space therebetween. The working fluid is sealed in the internal space. The microchannel is in the lower casing sheet and in communication with the internal space so as to form a flow path for the working fluid. The wick is in the internal space of the casing and is in contact with the microchannel. A contact area between the wick and the microchannel is 5% to 40% with respect to an area of the internal space taken as a plane.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a vapor chamber.

Description of the Related Art

Japanese Patent Application Laid-Open No. 2019-20001 discloses a vaporchamber that includes an upper casing sheet 6 having a column 3, a lowercasing sheet 7 having a protrusion 5, and a wick 4 disposed in a sealedspace between the upper casing sheet 6 and the lower casing sheet 7 andsandwiched between the protrusion 5 and the column 3. The upper casingsheet 6 and the lower casing sheet 7 seal a working fluid such as waterin an internal space therebetween.

The working fluid is vaporized by heat from a heat source, moves in theinternal space, and then releases heat to the outside to return to aliquid state. The working fluid that has returned to the liquid statemoves between the columns 3 by a capillary force of the wick 4, returnsto the vicinity of the heat source again, and evaporates again.Accordingly, the vapor chamber can diffuse heat at high speed by usingthe latent heat of evaporation and the latent heat of condensation ofthe working fluid without requiring external power.

SUMMARY OF THE INVENTION

In a vapor chamber, it is important to prevent a decrease in the maximumheat transport amount. For example, when an amount of heat transmittedto a wick decreases, the maximum heat transport amount decreasessignificantly. When an opening of the wick is small, an amount of aworking fluid vaporized is not enough, and the maximum heat transportamount also decreases significantly.

Thus, one embodiment of the present invention relates to a vapor chamberdesigned to prevent a decrease in the maximum heat transport amount.

The vapor chamber according to one embodiment of the present inventionhas the following configuration in order to solve this problem.

The vapor chamber includes a casing, a working fluid, a microchannel,and a wick. The casing includes an upper casing sheet and a lower casingsheet that face each other and are joined together at an outer edge soas to define an internal space therebetween. The working fluid is sealedin the internal space. The microchannel is in the lower casing sheet andin communication with the internal space so as to form a flow path forthe working fluid. The wick is in the internal space of the casing andis in contact with the microchannel. A contact area between the wick andthe microchannel is 5% to 40% with respect to an area of the internalspace taken as a plane.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a vapor chamber 1 according to oneembodiment of the present invention;

FIG. 2 is a plan view of a lower casing sheet 7;

FIG. 3 is a plan view of a wick 4;

FIG. 4 is a plan view in which the lower casing sheet 7 and the wick 4are overlapped through a portion of the wick 4;

FIG. 5 is an enlarged sectional view of the vapor chamber 1;

FIG. 6 is an enlarged partial sectional view of the vapor chamber 1;

FIG. 7 is an enlarged sectional view of the wick 4;

FIG. 8 is an enlarged sectional view of the wick 4;

FIG. 9 is a plan view of a further configuration of the wick 4; and

FIG. 10 is a plan view of yet another configuration of the wick 4.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a sectional view of a vapor chamber 1 according to oneembodiment of the present invention. FIG. 2 is a plan view of a lowercasing sheet 7. FIG. 3 is a plan view of a wick 4. All the drawings ofthe present embodiment are schematically shown for ease of explanation,and are not drawn to scale or otherwise show the actual size of thecomponents depicted therein.

The vapor chamber 1 includes a flat casing 10. The casing 10 has anupper casing sheet 6, the lower casing sheet 7, and a joining member 8.The upper casing sheet 6 and the lower casing sheet 7 are joinedtogether at an outer edge by the joining member 8. As shown in the planview of FIG. 4, the joining member 8 is disposed outside a broken lineshown at the outer edge of the lower casing sheet 7. The joining member8 is formed of, for example, a phosphor copper brazing filler.

The casing 10 has an internal space between the upper casing sheet 6 andthe lower casing sheet 7. A working fluid 20 such as water is sealed inthe internal space. The upper casing sheet 6 has a support 3 disposed inthe internal space. The lower casing sheet 7 has a microchannel 5disposed in the internal space.

The upper casing sheet 6 and the lower casing sheet 7 are formed ofcopper, nickel, aluminum, magnesium, titanium, iron, or an alloy mainlycomposed of these metals (for example, a nickel copper alloy or phosphorbronze), for example, and have a high thermal conductivity. In thepresent embodiment, the upper casing sheet 6 and the lower casing sheet7 are rectangular in a plan view of the vapor chamber. However, theupper casing sheet 6 and the lower casing sheet 7 may be polygonal orcircular in the plan view. The shape of the internal space may be anyshape.

As shown in FIG. 2, the microchannel 5 is a concavoconvex shaped portionhaving a plurality of prism-shaped convexes. The concavoconvexes of themicrochannel 5 are formed, for example, by etching an upper surface ofthe lower casing sheet 7. However, the concavoconvex shape of themicrochannel 5 is not limited to a prism. The concavoconvex shape of themicrochannel 5 may be, for example, a column.

When the concavoconvexes of the microchannel 5 are formed by etching,the concavoconvex shape of the microchannel 5 is typically a truncatedpyramid shape. The concavoconvexes of the microchannel 5 may be arrangedin a lattice (i.e., uniformly aligned in two directions with an angle θ₂therebetween), may be arranged in a honeycomb pattern, or may berandomly arranged.

The support 3 is a column for maintaining the thin plate shape of thevapor chamber 1. The support 3 is formed by etching a portion of theupper casing sheet 6 other than the support 3. The support 3 preferablyhas a prism shape. However, the shape of the support 3 is not limited toa prism. The shape of the support 3 may be, for example, a column. Asectional area of the support 3 is larger than a sectional area of theconvex of the microchannel 5, and an interval between the adjacentsupports 3 is larger than a pitch of the convexes of the microchannel 5.

The wick 4 is disposed in the internal space so as to be sandwichedbetween the lower casing sheet 7 and the support 3. The wick 4 is formedof a metal material thinner than the upper casing sheet 6 and the lowercasing sheet 7. The wick 4 is preferably adhesive bonded (diffusionbonded) to the microchannel 5 of the lower casing sheet 7. The wick 4may be formed of the same material as or different materials from theupper casing sheet 6 and the lower casing sheet 7. As shown in FIG. 3,the wick 4 is rectangular in the plan view. However, the wick 4 may bepolygonal or circular in the plan view. The shape of the wick 4 isappropriately set according to the shape of the internal space.

The wick 4 has a plurality of holes 41. The holes 41 are formed by, forexample, etching. In the example of FIG. 3, the holes 41 are circularbut may be rectangular. However, when the holes 41 are circular, agas-liquid interface becomes spherical, and the working fluid 20 can beuniformly evaporated.

The holes 41 are preferably arranged in a honeycomb pattern. In theexample of FIG. 3, an angle θ₁ formed between any given hole 41 and twoadjacent holes 41 is 60°. However, θ₁ may be, for example, 45°. Theholes 41 may be arranged in a lattice. Of course, the holes 41 may bearranged irregularly. The working fluid 20 changes from a liquid to agas in the holes 41 due to heat from a heat source close contact withthe lower casing sheet 7. That is, the working fluid 20 forms thegas-liquid interface in the holes 41. The vaporized working fluid 20emits heat in the internal space of the casing 10 and returns to aliquid state. The working fluid 20 that has returned to the liquid statemoves through the microchannel 5 due to a capillary force from the hole41 of the wick 4 and is transported again near the heat source.Accordingly, the vapor chamber 1 can diffuse heat at high speed by usingthe latent heat of evaporation and the latent heat of condensation ofthe working fluid 20 without requiring external power.

In the vapor chamber 1 of the present embodiment, a strong capillaryforce is secured by the holes 41 of the wick 4 having a relatively smallopening area, and a transmission sectional area of the working fluid 20(transmission amount of the working fluid 20) is secured by themicrochannel 5 having a relatively large opening area.

The vapor chamber 1 of the present embodiment has the followingfeatures.

(1) In the plan view, an area of the wick 4 is larger than an area of aregion corresponding to the microchannel 5.

FIG. 4 is a plan view in which the lower casing sheet 7 and the wick 4are overlapped through a portion of the wick 4. The wick 4 is wider inthe plan view than the width of the microchannel 5. The wick 4 issandwiched between the lower casing sheet 7 and the support 3, but maybe shifted in a plane direction of the casing sheet 7. However, the wick4 is wider in the plan view than the area of the region corresponding tothe microchannel 5. Preferably, the entire area of the wick 4 is largerthan the entire area of the microchannel 5. Accordingly, even if thewick 4 is shifted in the plane direction, a possibility that the wick 4comes out of the region where the microchannel 5 is disposed is reduced.

The wick 4 is formed by being cut out from one mother sheet, such as acopper plate. In the wick 4, a burr may be formed at a peripheral edgein a cutting step. Accordingly, as shown in FIG. 5, the peripheral edgeof the wick 4 may be separated and floated from the lower casing sheet 7by the burr. When the wick 4 separates from the lower casing sheet 7,the heat from the heat source becomes less likely to be transmitted tothe wick 4. However, since the wick 4 is wider in the plan view than thearea of the region corresponding to the microchannel 5, even if theperipheral edge is floated, floating from the lower casing sheet 7 canbe suppressed in the region corresponding to the microchannel 5.Accordingly, the wick 4 can ensure suitable heat conduction from themicrochannel 5.

A length h1 from a peripheral edge of the microchannel 5 to peripheraledge of the wick 4 is preferably not less than a height h2 of the burr.If h1 h2, even if the peripheral edge of the wick 4 is floated, an areaof floating from the lower casing sheet 7 can be sufficiently suppressedin the region where the microchannel 5 is disposed, and suitable heatconduction can be ensured.

(2) A contact area between the wick 4 and the microchannel 5 is 5% to40% with respect to an area of the internal space taken as a plane. Thecontact area between the wick 4 and the microchannel 5 is morepreferably 10% to 20% with respect to the area of the internal spacetaken as a plane.

In FIG. 4, the convexes of the microchannel 5 in contact with the wick 4are indicated by hatching. The area of the internal space taken as aplane is an area of an inner region indicated by the dashed line in thefigure. The outside of the dashed line is a portion joined by thejoining member 8 and is not part of the area of the internal space takenas a plane.

In the vapor chamber 1, when the contact area between the wick 4 and themicrochannel 5 is lower than 5% with respect to the area of the internalspace taken as a plane, the amount of heat transmitted from themicrochannel 5 to the wick 4 becomes low, and no gas-liquid interfacecan be formed at the hole 41 of the wick 4. In this case, the maximumheat transport amount decreases significantly. When the contact areabetween the wick 4 and the microchannel 5 exceeds 40% with respect tothe area of the internal space taken as a plane, the amount of theworking fluid 20 vaporized from the hole 41 of the wick 4 is not enough,and the maximum heat transport amount decreases significantly.Accordingly, when the contact area between the wick 4 and themicrochannel 5 is 5% to 40% with respect to the area of the internalspace taken as a plane, the vapor chamber 1 can ensure a predeterminedmaximum heat transport amount.

When the area of the wick 4 is larger than the area of the regioncorresponding to the microchannel 5 as in the above (1), the contactarea includes an area where the wick 4 is in contact with the lowercasing sheet 7, and is preferably 5% to 40% with respect to the area ofthe internal space taken as a plane.

(3) An opening width W1 of the microchannel 5 is preferably 50 to 200μm, a thickness D2 of the wick 4 is preferably 5 to 35 μm, andpreferably D2:W1=5:200 to 30:50.

More preferably, the thickness D2 of the wick 4 is 15 to 20 μm, and theopening width W1 of the microchannel 5 is 200 μm.

FIG. 6 is an enlarged partial sectional view of the vapor chamber 1.FIG. 6 shows a height D1 of the microchannel 5, the thickness D2 of thewick 4, the opening width W1 of the microchannel 5, a width W2 of theconvex of the microchannel 5, an opening pitch P1 of the microchannel 5,and an opening pitch P2 of the wick 4.

When the thickness D2 of the wick 4 is small and the opening width W1 ofthe microchannel 5 is large, the wick 4 sinks into an opening portion ofthe microchannel 5, and a gas-liquid interface of the working fluid 20is not formed at the holes 41 of the wick 4. Accordingly, the thicknessD2 of the wick 4 is preferably 5 μm or more, and the opening width W1 ispreferably 500 μm or less. On the other hand, if the thickness D2 of thewick 4 is too large, heat becomes less likely to be transmitted from theheat source in contact with the lower casing sheet 7. Accordingly, thethickness D2 of the wick 4 is preferably 35 μm or less. If the openingwidth W1 is too small, the transmission sectional area of the workingfluid 20 decreases. Accordingly, the opening width W1 of themicrochannel 5 is preferably 50 μm or more.

As the thickness D2 of the wick 4 increases, heat is less likely to betransmitted from the heat source. Therefore, it is necessary to reducethe opening width W1 to increase the contact area between the wick 4 andthe microchannel 5, thereby ensuring heat conduction. According, in thevapor chamber 1, when D2:W1=5:200 to 30:50, a predetermined maximum heattransport amount can be ensured.

(4) In the plan view, an area ratio of the convexes of the microchannel5 to the entire microchannel 5 is preferably 5% to 40%.

The working fluid 20 returns from a gas to a liquid and passes throughan opening of the microchannel 5. Accordingly, the smaller the number ofthe convexes constituting a flow path of the working fluid 20 is, thelarger the transmission sectional area of the working fluid 20 becomes.However, when an area of the opening of the microchannel 5 is too large,the wick 4 sinks into the opening portion of the microchannel 5, and thegas-liquid interface of the working fluid 20 is not formed at the holes41 of the wick 4. Accordingly, in the plan view, a ratio of the area ofthe convexes to the entire microchannel 5 is preferably at least 5% ormore.

On the other hand, if the area of the opening of the microchannel 5 istoo small, the transmission sectional area of the working fluid 20becomes small, and the maximum heat transport amount decreases.Accordingly, in the plan view, the ratio of the area of the convexes tothe entire microchannel 5 is preferably at most 40% or less.

In the plan view, the ratio of the area of the convexes to the entiremicrochannel 5 is more preferably 18 to 30%.

(5) In the plan view, the area ratio of the convexes of the microchannel5 to the entire microchannel 5 is preferably 5% to 40%, and the heightD1 of the convex of the microchannel 5 is preferably 5 to 50 μm.However, when D1 is 50 μm, the area ratio is preferably 40%.

As described above, when the area of the opening of the microchannel 5is too large, the wick 4 sinks into the opening portion of themicrochannel 5, and the gas-liquid interface of the working fluid 20 isnot formed at the holes 41 of the wick 4. On the other hand, if the areaof the opening of the microchannel 5 is too small, the transmissionsectional area of the working fluid 20 becomes small, and the maximumheat transport amount decreases.

When the height D1 of the convex of the microchannel 5 is too low, thetransmission sectional area of the working fluid 20 becomes small, andthe maximum heat transport amount decreases. On the other hand, if theheight D1 of the convex of the microchannel 5 is too high, a distancefrom the heat source to the wick 4 becomes lengthy, so that heat becomesless likely to be transmitted from the heat source.

Thus, in the vapor chamber 1, in order to prevent sinking of the wick 4while ensuring heat conduction and the transmission sectional area ofthe working fluid, in the plan view, the area ratio of the convexes ofthe microchannel 5 to the entire microchannel 5 is preferably 5% to 40%,and the height D1 of the convex of the microchannel 5 is preferably 5 to50 μm. However, when D1 is 50 μm, since heat from the heat source ismost difficult to be transmitted to the wick 4, the area ratio of theconvexes is set to about 40%, which is the highest ratio, to ensure heatconduction.

(6) An opening ratio of the holes of the wick (the area of the holes 41with respect to the entire area of the wick 4) is preferably 5 to 50%,the thickness D2 of the wick is preferably 5 to 35 μm, the sectionalarea of the convex of the microchannel 5 is preferably (D1×W2)=150 to25000 μm², and the pitch P1 (W1+W2) of the convexes of the microchannel5 is preferably 100 to 1000 μm. The pitch P1 is more preferably 100 to500 μm.

If the thickness of the wick 4 is too large, heat becomes less likely tobe transmitted from the heat source. On the other hand, if the thicknessof the wick 4 is too thin, the wick 4 sinks into the opening portion ofthe microchannel 5. If the opening ratio of the wick 4 is too high, heatbecomes less likely to be transmitted from the heat source. On the otherhand, if the opening ratio of the wick 4 is too low, an evaporationamount of the working fluid 20 decreases, and the maximum heat transportamount decreases. However, when D2 is 35 μm, heat from the heat sourceis most difficult to be transmitted to the wick 4, so that the openingratio is preferably set to about 5%, which is the lowest ratio, toensure heat conduction.

When the sectional area of the convex of the microchannel 5 is too smalland the pitch is too large, the wick 4 sinks into the opening portion ofthe microchannel 5. When the sectional area of the convex of themicrochannel 5 is too large and the pitch is too small, the transmissionsectional area of the working fluid 20 becomes small, and the maximumheat transport amount decreases.

Accordingly, in the vapor chamber 1, in order to prevent sinking of thewick 4 while ensuring heat conduction and the transmission sectionalarea of the working fluid, the opening ratio of the holes of the wick(the area of the holes 41 with respect to the entire area of the wick 4)is preferably 5 to 50%, the thickness D2 of the wick is preferably 5 to35 μm, the sectional area of the convex of the microchannel 5 ispreferably (D1×W2)=150 to 25000 μm², and the pitch P1 (W1+W2) of theconvexes of the microchannel 5 is preferably 100 to 1000 μm.

(7) A ratio of an opening width L1 on a first surface (upper surface)side of the hole 41 of the wick 4 to an opening width L2 on a secondsurface (lower surface) side of the hole 41 of the wick 4 is preferably1:3 to 1:1.

FIG. 7 is an enlarged sectional view of the wick 4. The holes 41 of thewick 4 are preferably formed by etching. When the etching is in an idealstate, the ratio of the opening width L1 on the upper surface side ofthe holes 41 of the wick 4 and the opening width L2 on the lower surfaceside is 1:1.

When a taper is formed during formation of the holes 41, or when thetaper is intentionally generated, if the ratio of the opening width L1on the upper surface side and the opening width L2 on the lower surfaceside is too large, the capillary force is reduced. Thus, in the vaporchamber 1, the ratio of the opening width L1 on the upper surface sideand the opening width L2 on the lower surface side is preferably 1:3 orless.

In FIG. 7, as an example, L1=40 μm, and L2=55 μm. In addition, thefollowing equations may be established that L1=30 μm and L2=100 μm. Thefollowing equations may be established that L1=40 μm and L2=40 μm.

In the example of FIG. 7, the side with the smaller diameter of the holeis disposed on the gas-liquid interface side which is the upper surfaceside, and the side with the larger diameter of the hole is disposed onthe microchannel side which is the lower surface side. However, the sidewith the smaller diameter of the hole may be disposed on the lowersurface side, and the side with the larger diameter of the hole may bedisposed on the upper surface side.

In all the holes 41, the ratio of the opening width L1 on the uppersurface side and the opening width L2 on the lower surface side does notneed to be 1:3 to 1:1. The number of holes 41 satisfying the ratio maybe 90% or more relative to the total number of the holes. As shown inFIG. 8, when the amount of etching increases, the lower surface side ofthe wick 4 is shaved, and a portion not being in contact with themicrochannel 5 may be generated. In this case, although an amount ofheat conduction is reduced in the portion not being in contact with themicrochannel 5, the transmission amount of the working fluid 20 isimproved because the working fluid 20 transmits within a gap between thewick 4 and the microchannel 5.

(8) A difference between a thickness of the joining member 8 and thethickness of the wick 4 is preferably 20 μm or less.

The difference between the thickness of the joining member 8 and thethickness of the wick 4 is more preferably 10 μm or less. For example,the thickness of the joining member 8 of the present embodiment is 25μm, and the thickness of the wick 4 is 15 μm. Thereby, smoothness of thecasing 10 is improved. Accordingly, a sealing performance by the joiningmember 8 is improved. The joining member 8 has an inlet (not shown) forinjecting the working fluid 20. When a vertical position of the inlet isabout the same as the position of the wick 4, the vapor chamber 1 caninject the working fluid 20 from the inlet directly into the wick 4, andthe working fluid 20 can be easily injected.

(9) The pitch P1 of the convexes of the microchannel 5 and a pitch P2 ofthe holes 41 of the wick 4 are not integral multiples.

For example, the pitch P1=350 μm, and the pitch P2=60 μm. In this case,an end of the hole 41 and an end of the convex are less likely tooverlap in the plan view. Accordingly, the wick 4 becomes less likely tosink into the opening of the microchannel 5.

(10) The wick 4 preferably has a region where the holes 41 are notformed in the plan view, a width W3 of a portion constituting thisregion is 0.1 to 10 mm, and an area of this region is 90% or less of thearea of wick 4 in the plan view.

When the portions constituting this region are regularly arranged, apitch P3 is 0.1 to 10 mm.

FIG. 9 is a plan view of a wick 4 having the region where the holes 41are not formed. In FIG. 9, for the sake of explanation, the number ofholes 41 greater in number than that in FIG. 3, and the holes 41 aresmaller in size than that in FIG. 3. In this example, the region wherethe holes 41 are not formed are linear portions arranged in a lattice.The width W3 of each linear portion forming the lattice is 0.1 mm. Thepitch P3 is 0.26 mm.

As described above, the wick 4 has the region where the holes 41 are notformed, the width W3 of the narrowest portion among the portionsconstituting the region is 0.1 to 10 mm, and the area of the region is90% or less of the area of wick 4 in the plan view, so that adhesivenessto the microchannel 5 is improved, and the adhesive bonding is uniform.Accordingly, even if an impact such as a drop is applied to the vaporchamber 1 or a stress is generated at the time of bending, the wick 4 isless likely to lift from the microchannel 5. Thus, the vapor chamber 1can suppress a change in the maximum heat transport amount.

The portion constituting this region is not limited to the example ofFIG. 9. For example, as shown in FIG. 10, the portions constituting thisregion may be arranged diagonally. The portions constituting this regionalso need not be regularly arranged. The portions constituting theregion may be randomly arranged in a random shape.

The description of the present embodiment is to be considered in allrespects as illustrative and not limiting. The scope of the presentinvention is indicated not by the above embodiments but by the claims.The present invention includes all alterations within the implicationand scope of the features described herein, and is to only be limited bythe claims. For example, all or some the above-described features (1) to(10) may be combined.

What is claimed is:
 1. A vapor chamber comprising: a casing including anupper casing sheet and a lower casing sheet that face each other and arejoined together at an outer edge so as to define an internal spacetherebetween; a working fluid in the internal space; a microchannel inthe lower casing sheet and in communication with the internal space soas to form a flow path for the working fluid; and a wick in the internalspace of the casing and in contact with the microchannel, wherein thewick includes a plurality of holes uniformly aligned with both a firstdirection and a second direction, the microchannel includes a pluralityof convexes uniformly aligned with both a third direction and a fourthdirection, a first angle (θ1) between the first direction and the seconddirection is different from a second angle (θ2) between the thirddirection and the fourth direction, and a contact area between the wickand the plurality of convexes of the microchannel is 5% to 40% withrespect to an area of the internal space taken as a plane.
 2. The vaporchamber according to claim 1, wherein the contact area is 10% to 20%with respect to the area of the internal space taken as the plane. 3.The vapor chamber according to claim 1, further comprising a joiningmaterial that joins the upper casing sheet to the lower casing sheet atthe outer edge.
 4. The vapor chamber according to claim 3, wherein thearea of the internal space taken as the plane is an area of an innerregion of the vapor chamber defined by the joining material.
 5. Thevapor chamber according to claim 3, wherein a difference between athickness of the joining material and a thickness of the wick is 20 μmor less.
 6. The vapor chamber according to claim 1, wherein theplurality of convexes are prism-shaped.
 7. The vapor chamber accordingto claim 6, wherein an area ratio of a total area of all of theplurality of prism-shaped convexes of the microchannel to an entirety ofan area of the microchannel is 5% to 40% in a plan view of the vaporchamber.
 8. The vapor chamber according to claim 7, wherein a height ofthe plurality of prism-shaped convexes of the microchannel is 5 to 50μm.
 9. The vapor chamber according to claim 6, wherein a first pitch ofthe plurality of prism-shaped convexes of the microchannel and a secondpitch of holes in the wick are not integral multiples.
 10. The vaporchamber according to claim 1, further comprising a support in the uppercasing sheet, the wick being between the support and the lower casingsheet.
 11. The vapor chamber according to claim 1, wherein the wick isbonded to the microchannel.
 12. The vapor chamber according to claim 1,wherein the wick includes a plurality of circular holes.
 13. The vaporchamber according to claim 1, wherein an area of the wick is larger thanan area of a region corresponding to the microchannel in a plan view ofthe vapor chamber.
 14. The vapor chamber according to claim 1, whereinthe wick is wider in a plan view of the vapor chamber than a width ofthe microchannel.
 15. The vapor chamber according to claim 1, whereinthe wick is flat.
 16. The vapor chamber according to claim 1, wherein anopening width W1 of the microchannel is 50 to 200 μm, a thickness D2 ofthe wick is 5 to 35 μm, and D2: W1=5:200 to 30:50.
 17. The vapor chamberaccording to claim 16, wherein the thickness D2 of the wick is 15 to 20μm, and the opening width W1 of the microchannel is 200 μm.
 18. Thevapor chamber according to claim 1, wherein an opening ratio of an areaof holes in the wick with respect to an entire area of the wick is 5 to50%.
 19. The vapor chamber according to claim 1, wherein a ratio of afirst opening width on a first surface side of a hole in the wick to asecond opening width on a second surface side of the hole in the wick is1:3 to 1:1.
 20. The vapor chamber according to claim 1, wherein the wickhas a region where holes are not formed therein in a plan view of thevapor chamber, a width of a narrowest portion of the region is 0.1 to 10mm, and an area of the region is 90% or less of an entire area of thewick in the plan view.